Ansible deploy on multiple hosts in the same time

Question

Is it possible to run ansible playbook  which looks like this  it is an example from this site  http   docs ansible com playbooks roles html    - name  this is a play at the top level of a file   hosts  all   remote user  root   tasks    - name  say hi     tags  foo     shell  echo  hi      - include  load balancers yml - include  webservers yml - include  dbservers yml   in multithread mode   I want to run three  includes  in the same time  it is deploying to different hosts anyway   like in this diagram   http   www gliffy com go publish 5267618  Is it possible

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Ansible supports patterns which can be used for one multiple hosts groups and also can exclude include groups  Here is the link for official document

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By default Ansible will attempt to run on all hosts in parallel   See these Ansible docs for details   You can also use the serial parameter to limit the number of parallel hosts you want to be processed at any given time  so if you want to have a playbook run on just one host at a time you can specify serial 1  etc   Ansible is designed so that each task will be run on all hosts before continuing on to the next task   So if you have 3 tasks it will ensure task 1 runs on all your hosts first  then task 2 is run  then task 3 is run   See this section of the Ansible docs for more details on this

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As of Ansible 2 0 there seems to be an option called strategy on a playbook  When setting the strategy to free  the playbook plays tasks on each host without waiting to the others  See http   docs ansible com ansible playbooks strategies html   It looks something like this  taken from the above link    - hosts  all   strategy  free   tasks          Please note that I didn t check this and I m very new to Ansible  I was just curious about doing what you described and happened to come acroess this strategy thing   EDIT   It seems like this is not exactly what you re trying to do  Maybe  async tasks  is more appropriate as described here  http   docs ansible com ansible playbooks async html   This includes specifying async and poll on a task  The following is taken from the 2nd link I mentioned   - name  simulate long running op  allow to run for 45 sec  fire and forget   command   bin sleep 15   async  45   poll  0   I guess you can specify longer async times if your task is lengthy  You can probably define your three concurrent task this way

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I played a long time with things like ls -1   xargs -P to parallelize my playbooks runs  But to get a prettier display  and simplicity I wrote a simple Python tool to do it  ansible-parallel  It goes like this  pip install ansible-parallel ansible-parallel   yml  To answer precisely to the original question  how to run some tasks first  and the rest in parallel   it can be solved by removing the 3 includes and running  ansible-playbook say hi yml ansible-parallel load balancers yml webservers yml dbservers yml

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Check out this POC or MVP of running in parallel one-host-from-every-group  for all hosts  https   github com sirkubax szkolenie3 tree master playbooks playgroups  you may get the inspiration

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As mentioned before  By default Ansible will attempt to run on all hosts in parallel  but task after Task serial    If you also want to run Tasks in parallel you have to start different instances of ansible  Here are some ways to to it   1  Groups  If you already have different groups you can run one ansible instance for each group   shell-1   gt  ansible-playbook site yml --limit webservers shell-2   gt  ansible-playbook site yml --limit dbservers shell-3   gt  ansible-playbook site yml --limit load balancers   2  Multiple shells  Playbooks  If your playbooks work standalone you can although do this   shell-1   gt  ansible-playbook load balancers yml shell-2   gt  ansible-playbook webservers yml shell-3   gt  ansible-playbook dbservers yml   Limit  If not  you can let ansible do the fragmentation  When you have 6 hosts and want to run 3 instances with 2 host each  you can do something like this   shell-1   gt  ansible-playbook site yml --limit all 0-2  shell-2   gt  ansible-playbook site yml --limit all 2-4  shell-3   gt  ansible-playbook site yml --limit all 4-6    3  Background  Of course you can use one shell and put the tasks in background  an simple example would be   shell-1   gt  ansible-playbook site yml --limit all 0-2   amp  shell-1   gt  ansible-playbook site yml --limit all 2-4   amp  shell-1   gt  ansible-playbook site yml --limit all 4-6   amp    With this method you get all output mixed together in one terminal  To avoid this you can write the output to different files   ansible-playbook site yml --limit all 0-2   gt  log1  amp  ansible-playbook site yml --limit all 2-4   gt  log2  amp  ansible-playbook site yml --limit all 4-6   gt  log3  amp    4  Better Solutions  Maybe it s better to use a tool like tmux   screen to start the instances in virtual shells   Or have a look at the  fireball mode   http   jpmens net 2012 10 01 dramatically-speeding-up-ansible-runs   If you want to know more about limits  look here  https   docs ansible com playbooks best practices html what-this-organization-enables-examples

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In my case I needed the configuration stage to be blocking as a whole  but execute each role in parallel  I ve tackled this issue using the following code   echo webserver loadbalancer database   tr       n      xargs -I   -P 3 bash -c  ansible-playbook  1 yml  --     the -P 3 argument in xargs makes sure that all the commands are ran in parallel  each command executes the respective playbook and the command as a whole blocks until all parts are finished

[ansible] Ansible: deploy on multiple hosts in the same time

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